If you have a cable pull valve:
Once you get underneath and get to the valve, you will find they do NOT cut the cables to length. Instead, just coil the cable and Tye wrap it together. This is how they did my pull cable runs. You can shorten the cables with a good pair of wire cutters and a Dremel. I used the Dremel tool and cut the outer covering on the cable, then the wire cable to length.
The cable is held to the valve body with an Allen screw, it could had backed off, so make sure it is tight as well. The inner wire goes thru the hole and the outer cable seats in the same spot. The Allen screw is tightened to hold it in place.
If you go to remove the valve, make sure the tank is empty. The raise the camper high on the discharge side, so the tank will not drain on you when you take the valve body out. Experience on that.